Hazardous waste materials are frequently transported to disposal facilities in very large waste handling containers. A typical such container might measure 8'.times.18'.times.5' with an opening in the top thereof measuring 7'.times.14'. To safely close off this large opening, a one-piece lid must cover the entire opening and form a tight seal against the container body to prevent the hazardous materials from escaping during transport.
One example of such a lid is shown in U.S. Pat. No. 4,934,562 wherein the lid has a downwardly extending, longitudinal flange which rides along rollers positioned on top of the container. A complicated screw-type mechanism is used to raise the lid from a sealed position, and then the lid is slid laterally along the rollers roughly half its width until a pair of spring-biased hooks catch corresponding hinge bars at the edge of the top of the container. The lid is thus hingedly connected to the top of the container and is pivoted to the side and out of the way of the opening. In addition to the significant risk of failure of the screw mechanism to unseal and raise the lid and the difficulty of servicing the screw mechanism, the lid can easily be de-railed from its tracks. Moreover, although fairly heavy, this lid has proven to be highly susceptible to the forces of a good wind gust which has picked the lid up, off and away from the container. It has also been found that the special spring-biased hooks do not reliably engage with the hinge members. This can and has left the lid skewed, de-railed, and jammed. Another example of this general type of sliding lid configuration is shown in U.S. Pat. No. 4,821,902. Here, the lid of a large waste container is supported for gliding horizontal movement atop rollers mounted to the top of the container.
These large waste containers are often transported by rail where maximum container height limits are set by the applicable federal regulation. To maximize the container volume, while staying within the container height limitations, it is desired that the mechanism for supporting the container lid for sliding and pivoting movement project above the container as little as possible.
What is needed is a simple and reliable, but low rising mechanism for permitting the lid of a large hazardous waste handling container to be easily manipulated between a locked and sealed position and an open position clear of the corresponding container opening.